The Caribbean Monk Seal

The Caribbean Monk Seal was last seen in 1952, after it was systematically killed off for during the 18th and 19th Centuries for its oil reserves. Like much of its mammalian brethren, the poor seals were friendly and docile, which hastened their extinction. Surprisingly little was done to save the seal; it was only added to the endangered species list in 1967, over a decade after it went extinct.